title: Tropical aquatic Archaea show environment-specific community composition.
abstract: The Archaea domain is ubiquitously distributed and extremely diverse, however, environmental factors that shape archaeal community structure are not well known. Aquatic environments, including the water column and sediments harbor many new uncultured archaeal species from which metabolic and ecological roles remain elusive. Some environments are especially neglected in terms of archaeal diversity, as is the case of pristine tropical areas. Here we investigate the archaeal composition in marine and freshwater systems from Ilha Grande, a South Atlantic tropical environment. All sampled habitats showed high archaeal diversity. No OTUs were shared between freshwater, marine and mangrove sediment samples, yet these environments are interconnected and geographically close, indicating environment-specific community structuring. Group II Euryarchaeota was the main clade in marine samples, while the new putative phylum Thaumarchaeota and LDS/RCV Euryarchaeota dominated freshwaters. Group III Euryarchaeota, a rare clade, was also retrieved in reasonable abundance in marine samples. The archaeal community from mangrove sediments was composed mainly by members of mesophilic Crenarchaeota and by a distinct clade forming a sister-group to Crenarchaeota and Thaumarchaeota. Our results show strong environment-specific community structuring in tropical aquatic Archaea, as previously seen for Bacteria.
authors.affiliation: Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, UFRJ, Rio de Janeiro, Rio de Janeiro, Brazil ; Departamento de Genética, Universidade Federal do Rio de Janeiro, UFRJ, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Cynthia B
authors.initials: CB
authors.lastname: Silveira
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Cardoso
authors.forename: Felipe H
authors.initials: FH
authors.lastname: Coutinho
authors.forename: Joyce L
authors.initials: JL
authors.lastname: Lima
authors.forename: Leonardo H
authors.initials: LH
authors.lastname: Pinto
authors.forename: Rodolpho M
authors.initials: RM
authors.lastname: Albano
authors.forename: Maysa M
authors.initials: MM
authors.lastname: Clementino
authors.forename: Orlando B
authors.initials: OB
authors.lastname: Martins
authors.forename: Ricardo P
authors.initials: RP
authors.lastname: Vieira
mesh_terms: D000220:Adaptation, Biological / Q000502:physiology*; D001105:Archaea / Q000502:physiology*; D001483:Base Sequence; D058448:Biota / Q000502:physiology*; D001938:Brazil; D017931:DNA Primers / Q000235:genetics; D004777:Environment; D015723:Gene Library; D019015:Geologic Sediments / Q000382:microbiology*; D016013:Likelihood Functions; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D014329:Tropical Climate; D014871:Water Microbiology
chemical_list: D017931:DNA Primers; D012336:RNA, Ribosomal, 16S